It is frequently necessary to transport medical patients from the site of an accident or injury to a hospital. For example, persons suffering from various medical emergency conditions such as heart attacks, and strokes must be transported quickly to a medical facility. Medical personnel speak of a "golden hour" within which such a medical patient must be transported to a medical facility so that proper medical care can be provided therefor. The survival rate for such medical patients is greatly enhanced if they are transported to the medical facility within the golden hour.
As those skilled in the art will appreciate, it is frequently difficult to transport a patient to a remotely located medical facility in a timely manner, particularly within the desired golden hour. It is not unusual for accidents to occur at remote locations. Thus, a substantial amount of time may be required to transport the medical patient to a distant hospital. Also, in battlefield situations it is frequently impossible to transport a casualty immediately. In either instance, the patient may be located hundreds, if not thousands, of miles from a hospital, thus necessitating several hours of transport time. As such, it is frequently beneficial to perform various emergency medical procedures at the site of the medical problem, and then to attempt to provide ongoing medical care during transport to a remote hospital. The mortality rate of such transported medical patients is substantially reduced.
It is well-known to use various different medical devices in the field, i.e., at locations remote from a medical facility, so as to enhance a medical patient's chance of survival. For example, it is well-known to use an ECG and a defibrillator upon heart attack victims so as to monitor the condition thereof and so as to provide medical treatment therefor in field.
Typically, the medical patient is placed upon a stretcher and then various different medical devices are used upon the patient, as necessary. During transport the medical devices may either be temporarily disconnected from the patient, or alternatively may be hand carried along therewith by additional personnel. However, disconnection of the medical devices from the patient results in the undesirable disruption of medical monitoring and/or treatment therefor. Hand carrying the medical devices along with the patient requires extra personnel, which may not be available, or for which there may not be adequate room within the transport vehicle.
As such, it is desirable to provide a system for transporting a medical patient wherein the medical devices are carried along with the stretcher. In an attempt to provide such a system for transporting a medical patient while facilitating the continuous use of medical devices thereupon, the Mobile Intensive Care Rescue Facility (MIRF) was developed by the Royal Australian Army Medical Corp. The MIRF is intended to provide sufficient medical equipment to have the capabilities of an intensive care hospital ward. The MIRF is designated so as to facilitate the removal and replacement of the various pieces of medical equipment therefrom for maintenance. The MIRF is specifically designed to accommodate two major roles: the transfer of critically ill people from one point to another, such as from a ward to an x-ray room or from one hospital to another; and the bringing of life support systems quickly to the scene of an accident or other medical emergency.
The MIRF can be configured to include a blood pressure cuff, an invasive blood pressure monitor, a body temperature sensor, a heart rate sensor (finger clip sensor), an oxygen saturation sensor, an exhaled air carbon dioxide sensor, and an electrocardiograph, so as to facilitate medical monitoring of a patient. Further, the MIRF can include a ventilation system, a volumetric infusion pump, a syringe pump, a suction unit, and a defibrillator so as to facilitate medical treatment.
Another contemporary system is the MOBI described in U.S. Letters Pat. No. 4,957,121, issued to Icenogle et al. on Sep. 18, 1990. The MOBI is similar to the MIRF in concept. That is, like the MIRF, the MOBI utilizes off-the-shelf medical devices which are attached to the housing thereof so as to be transportable therewith, thus eliminating disruptions in the medical care provided thereby during transport.
Further examples of such contemporary life support systems include those disclosed in U.S. Pat. Nos. 4,584,989; 4,352,991; 4,691,397; 3,304,116; and 3,341,246.
U.S. Pat. No. 4,584,989 discloses a life support stretcher bed adapted to accommodate patients in intensive or cardiac care units in hospitals. The life support stretcher bed is broadly adapted for electrical medical devices, medical supplies and features an undercarriage including a support structural, wheels, a patient housing with a mattress, an electrical power source and supports for mounting the medical equipment.
U.S. Pat. No. 4,352,991 teaches a life support system adapted for field use in a vehicle with available power and includes electrically operable life support units, means for supporting the life support units, a patient stretcher, and a DC power source adapted for battery or remote power source.
U.S. Pat. No. 4,691,397 teaches a device for carrying the life supporting devices of a bedridden patient including a table like means for supporting the devices, an IV holder, wheeled transport means and a hospital bed footboard securing means.
U.S. Pat. No. 3,341,246 teaches a hospital stretcher adapted broadly with a litter structure having telescopic post elements and other means for manipulating the patient to various positions.
As those skilled in the art will appreciate, it would further be desirable to monitor the operation of each of the medical devices so as to provide both medical personnel with useful information regarding the patient's condition. Medical personnel could then use the results of such monitoring to determine the condition of the patient as well as the treatment which must be provided to the patient.
Thus, when the transportable life system arrives at a medical facility, medical personnel could immediately access a hand-held or fixed display to determine the status of the patient. Rapid access to such information would greatly aid in the diagnosis and treatment of the patient. For example, if the patient has an irregular heart beat then medical personnel would immediately be alerted as to the need to continue with monitoring of the heart beat, as well as to the possible need to treat the irregularity.
The hand-held or fixed display may also be used by maintenance personnel to review an on-board data log so as to determine if the medical monitoring devices were monitoring the patient properly and if the medical treatment devices were applying treatment to the patient in the desired manner. Further, logged parameters such as the time in service for each medical device could be used to provide maintenance personnel with an easy means for determining when routine maintenance should be performed upon each medical device.
However, when the medical devices have previously been approved by a governmental agency such as the Food and Drug Administration (FDA) in the United States, then it is necessary that such monitoring thereof be accomplished without interfering with the operation of the medical devices, so as to attempt to maintain the validity of such prior governmental approval. Merely providing a direct electrical connection between those medical devices for which monitoring is desired and the monitor (or a computer which drives the monitor) is not suitable since such a direct connection has the potential to modify or load-down circuitry of the medical device. As those skilled in the art will appreciate, such modification of the circuitry of a medical device may adversely affect the operation thereof. For example, if the device includes a built in display, then tapping into the signals of that display may weaken the signals, thereby providing a false indication to the display. Thus, any signals associated with the medical devices must be taken in a manner which does not affect the performance of the medical device.
In view of the foregoing, it is desirable to provide a means for monitoring medical devices, i.e., medical monitoring devices and medical treatment devices, of a transportable life support system in a manner which does not invalidate prior governmental approval of the medical devices.